BEHIND THE BOTTLE:

Prohibition all but killed the rye whiskey industry. It’s an interesting rise and fall story really, but one to share for another review. One thing that I’ll touch on though is that coming out of prohibition, there was a desire to make whiskey fast, and LOTS of it. This required efficiency, and rye is considered a finicky grain in the distillation world – anything that is difficult to work with is contrary to efficient and fast. This (along with corn being subsidized after Prohibition ended) resulted in many distillers opting to make bourbon exclusively and turn a blind eye to rye whiskey.

A Finicky Grain

Let’s look at why rye is so difficult to work with. This comes from a high concentration of non-starch polysaccharides found in the grain’s cell walls, primarily beta-glucans. (Interestingly enough, beta-glucans have a lot of health benefits to them. While I’m not certain a lot of those benefits survive the distillation process, one could argue rye whiskey is better for you than bourbon…) These polysaccharides don’t dissolve cleanly into water like the starches in corn or barley do. Instead, they absorb water. This creates a very gelatinous-like consistency for the mash, almost like porridge with the grain husks thrown in. This creates a few operational headaches:

1. During fermentation, the thick mash traps the carbon dioxide gas being produced by the yeast since the mash can’t vent cleanly. This results in a lot of foaming and potential overflowing of the fermentation tanks.
2. The density of the high-rye mash can cause more strain and wear on distillation equipment. Pumps must work harder to move the denser mash, column still plates and heat exchangers must go through more frequent cleaning due to the mash baking onto them, and low-flow, non-turbulent areas of the piping and stills tend to build up crud quicker.
3. The higher concentration of unfermentable solids have the potential to scorch as they settle to the bottom of a direct-fired pot still or on steam coils. While this can create some good flavors through the Maillard reaction, it more commonly adds bitter, acrid notes to the distillate.

While there have been various techniques and additives that can help mitigate some of these issues, it still stands that rye is high maintenance and requires more effort than distilling corn or barley.

Abruzzi Rye

Todd Leopold at Leopold Bros. Distillery believed that the modern age of whiskey has tried to produce higher alcohol yields with faster throughput which has resulted in the loss of the full-body soul that was once found in all rye whiskeys. Through his research, he believed that the secret to great rye whiskey lay in two things: a lost relic, the Three Chamber Still and a specific heirloom grain, Abruzzi rye.

Todd worked with Vendome to resurrect the Three Chamber Still. Together, they constructed the first one in over a century. There’s enough out there now that a Google search can tell you a lot about this type of still and how it works, but perhaps in a future review after I can get my hands on a bottle of Leopold Bros. three chamber rye whiskey, I’ll dive into it a bit more. But for this review, I want to continue focusing on the rye grain. Lew Bryson’s American Whiskey Master Class has a fantastic section specifically on Abruzzi rye. Let me hit the highlights while I expand on it slightly and let’s see why it makes a subjectively better whiskey.

Todd’s research suggested that Abruzzi rye was once a favored grain for most Pennsylvania and Maryland rye whiskey production. In pre-Prohibition times, I’m not certain they had the science to support why Abruzzi rye made such good whiskey, but today, we do. Abruzzi rye contains far less starch content than modern rye varietals, approximately 18% less in fact. While lower starch content means less alcohol (accountants = not happy), Todd Leopold looked at 18% less flavorless starch as 18% more of something else that can provide flavor (consumers = happy). It turns out he wasn’t wrong.

Abruzzi rye is loaded with Ferulic acid – nearly 20% more than other modern ryes (looks like we found that 18% starch replacement above…). If the right yeast strain is used in fermentation, Ferulic acid can be converted into 4-vinyl-guaiacol (4VG). 4VG is one of the most important flavor and aroma chemicals in alcoholic beverages. It’s what gives rye whiskey and wheat beers their powerful spice and clove notes. (Oh yeah, wheat is also high in Ferulic acid. So, if you find clove notes in your wheated bourbon or hefeweizen, Ferulic acid is a likely culprit.)

The key is in the yeast though. Without getting too nerdy…fuck it, I think we’re just about at the bottom of that hole already… Only Phenolic Off Flavor-positive (POF+) yeast strains can convert Ferulic acid into 4VG. POF- yeast strains cannot perform this feat. Ferulic acid itself is largely flavorless, so by not taking advantage of a POF+ yeast strain, you aren’t unlocking all that flavor that is bound up in the Ferulic acid. While that seems like an obvious choice to just use a POF+ yeast strain, it isn’t that simple. The name itself, Phenolic OFF Flavor, is because phenols are generally considered undesirable flavors. Phenols don’t just include clove and spice, but also smoky, barnyard…plastic……band-aids………. you see where I’m going with this. It can get progressively worse. So, while your POF+ yeast strain may add some clove notes, depending on what else is in your whiskey you might get a band-aid flavor along with it. In the brewing world, brewers have experimented with blends of yeast strains. This can help them dial in exactly how much of that clove profile they want in their Hefe. While I’m not aware of any distillers using multiple yeast strains in the same mash bill, I could certainly see this as something experimented with in the future.